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PO240 error code - 02 sensor, bank 1

Discussion in '1st Gen. Tacomas (1995-2004)' started by thenrie, Mar 16, 2009.

  1. Mar 16, 2009 at 5:03 AM
    #1
    thenrie

    thenrie [OP] Well-Known Member

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    Stafford, VA
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    2000 Tacoma, SR5, TRD, 2.7L (LEV), 4wd, 5sp m
    Magnaflow cat and cat-back exhaust, AFE Stage 2 cold-air intake system, 2.5" lift via Skyjacker leaf packs, Bilstein 5100s.
    Ok, guys. Need a hand. My CEL came on a couple months ago, so I ignored it. Then it went off for about two weeks, then came on again. I had it reset by a friend with a code reader, but it came back on the next day (no surprise). The code indicates PO240 - O2 sensor, bank 1. Since it is a 4-banger, I only have "bank 1", so that's no mystery. I need to get an inspection to re-register my Taco in VA, so I need to fix it. I replaced the O2 sensor located aft of the rear cat about 6 months ago with a genuine Toyota unit. Is there another O2 sensor? My pickup is a LEV with two cats if that makes any dif. Anybody know specifically what PO-240 means?
     
  2. Mar 16, 2009 at 5:38 AM
    #2
    98tacoma27

    98tacoma27 is gooder 'en chicken Moderator

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    P0240 Turbocharger Boost Sensor B Circuit Range/Performance

    O2 sensor codes run from P0130-P0167
     
  3. Mar 16, 2009 at 5:41 AM
    #3
    98tacoma27

    98tacoma27 is gooder 'en chicken Moderator

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    Are you sure it wasn't a P0420 code? That is the one for the CAT.

    Oh, and what is LEV?
     
  4. Mar 16, 2009 at 5:43 AM
    #4
    98tacoma27

    98tacoma27 is gooder 'en chicken Moderator

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    Nevermind, Low Emissions Vehicle. It sounds like a CA truck.
     
  5. Mar 16, 2009 at 6:08 AM
    #5
    thenrie

    thenrie [OP] Well-Known Member

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    2000 Tacoma, SR5, TRD, 2.7L (LEV), 4wd, 5sp m
    Magnaflow cat and cat-back exhaust, AFE Stage 2 cold-air intake system, 2.5" lift via Skyjacker leaf packs, Bilstein 5100s.
    Here we go. I think I found what I need on another thread (funny that nothing popped when I used the search function). There are two sensors, Bank 1, Sensor 1 (before the cats) and Bank, 1 Sensor 2 (aft of the cats). I may have remembered the code wrong (PO240 or PO420), but I know it said "O2 Sensor, Bank 1". I just don't remember whether it said "O2 Sensor 1" or not. I suspect it did, since I recently replaced Bank 1, Sensor 2.

    Thanks for the input. Another mystery solved on Tacoma World!
     
  6. Mar 16, 2009 at 6:12 AM
    #6
    98tacoma27

    98tacoma27 is gooder 'en chicken Moderator

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    5100's all on fours
  7. Mar 16, 2009 at 11:08 AM
    #7
    thenrie

    thenrie [OP] Well-Known Member

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    Stafford, VA
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    2000 Tacoma, SR5, TRD, 2.7L (LEV), 4wd, 5sp m
    Magnaflow cat and cat-back exhaust, AFE Stage 2 cold-air intake system, 2.5" lift via Skyjacker leaf packs, Bilstein 5100s.
    Went and had it checked again. You were right, 98tacoma27. The code was PO420, indicating my cats are working below par. The tech suggested I try "Guaranteed To Pass", which is a fuel system cleaner that goes in the tank, before I spend the money for new cats. We'll see.

    Anywho...if the CEL doesn't go out in a week or so, I'll have to replace the cat(s). Since I have the Cal Low Emissions Vehicle model, which has two cats inline, anybody have any knowledge as to which cat (or both) I might need to replace? Anybody know whether those "high-flow" cats I see advertised offer any fuel mileage increase?
     
  8. Mar 16, 2009 at 11:40 AM
    #8
    chris4x4

    chris4x4 With sufficient thrust, pigs fly just fine. Moderator

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    The PO420 code could also be indicative of an exhaust leak. Check your exhaust to make sure there are no leaks anywhere near the manifold.
     
  9. Mar 19, 2009 at 1:46 PM
    #9
    thenrie

    thenrie [OP] Well-Known Member

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    Stafford, VA
    Vehicle:
    2000 Tacoma, SR5, TRD, 2.7L (LEV), 4wd, 5sp m
    Magnaflow cat and cat-back exhaust, AFE Stage 2 cold-air intake system, 2.5" lift via Skyjacker leaf packs, Bilstein 5100s.
    thanks for that tip. I'll try that first.
     
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